1. Field of the Invention
The invention relates to coating technology, and in particular to a waterproof, high contact angle, low stain and low mist adhesion coating.
2. Description of the Related Art
European Publication Number EP0772514 issued to Bartholtt in 1995, discloses hydrophobic self-cleaning material, and created a microstructured hydrophobic material. PCT Publication Number WO03008697 issued to Creavis Tech & Innovation GmbH in 2003, discloses other self-cleaning material and the hydrophobicity of the material was increased. However, both the disclosed surface microstructures exhibit poor resistance to external force, and the self-cleaning efficacy declines rapidly with time. U.S. Pat. No. 6,743,467 issued to Unisearch Limited in 2004, discloses using inorganic siloxane as precursors of crosslinker and gel, and then chemically modified to obtain a super hydrophobic material, but because the crosslinker is inorganic siloxane, a high reaction temperature is required to reach the desirable hydrophobicity.
The wettability of solid surfaces is determined by both the chemical composition and geometrical microstructure of the surface. Currently, hydrophobic surfaces with water contact angle higher than 130° are arousing much interest because they will bring great convenience in daily life as well as in many industrial processes. Various phenomena, such as contamination or oxidation, are expected to be inhibited on such a surface.
An important application of hydrophobic surface is self-cleaning coating by repelling water and dirt because of super low surface energy surface. These self-cleaning coatings not only provide value-added products with a high potential to save on cleaning and other maintenance costs, but also are good for the ecobalance of the coated product, since cleaning chemicals no longer pollute the water and energy is saved by reducing or eliminating maintenance cycles.
Conventionally, hydrophobic surfaces have been produced mainly in two ways. One is to create a rough structure on a hydrophobic surface, and the other is to modify a surface by materials with low surface free energy. Unfortunately, both approaches have several issues to deal with. Most hydrophobic coatings with surface roughness do not exhibit sufficient mechanical strength and adhesion, which results in short lifetimes. Others modified with low surface energy materials generally do not exhibit sufficient hydrophobicity (contact angle with water<130°) or adhesion.